ZrO_2ナノ微粒子を用いた高屈折率ー高アッベハイブリッド光学材料の創製

摘要

A versatile and promising organic-inorganic hybridization method is described for the fabrication of highly transparent organic-inorganic hybrid bulk materials containing highly crystalline ZrO_2 nanoparticles (NPs). The two key technologies are the surface-treatment, hydrophobization, and functionalization of ZrO_2 NPs originally dispersed in water and their nanodispersion into a polymer continuous phase without any coagulation and/or agglomeration. A unique and fascinating surface treatment method is demonstrated in which the hydrophobization and phase transfer of ZrO_2 NPs from water to toluene is simultaneously achieved. Transparent surface-modified ZrO_2 nanodispersions in toluene are obtained by a gentle solvent exchange from a ternary solvent mixture composed of water, toluene, and methanol. The surface-treated ZrO_2 NP powders after drying possess the ability of re-dissolution or nanodispersion in several organic solvents and vinyl monomers. Optically transparent polystyrene and poly(methyl methacrylate) hybrid bulk materials with thicknesses of 10 mm are fabricated. Furthermore, the technique is applied to the hybridization of ZrO_2 NPs and epoxy-based polymers. Their refractive indices and Abbe's numbers are quantitatively described by the Lorentz-Lorenz effective medium expansion theory. The present method provides promising candidates for different transparent hybrid optical materials consisting of inorganic and organic materials.%水中においてシングルナノサイズの光学補強剤微粒子を凝集させることなく高分子中にナノ分散できれば、透明性を損なうことなく有機材料の光学特性を制御できるものと期待されている。本稿では"微粒子に優しい"表面疎水•機能化および八イブリッド化手法について概説し、本手法が有機光学材料の高性能化に繋がる有望な方法になり得ることを展望したい。